Bushings are generally a cylindrical lining inserted into a cylindrical opening in order to limit the size of the opening, reduce friction and wear within the opening, provide a bearing surface, or guide motion.
U.S. Pat. No. 3,178,071 (Gentoso) describes a cap assembly using a bearing surface to permanently attach to an aerosol container. The cap has an inner lip created from an upwardly and inwardly extending portion of the cap material. The inner lip has two diametrically opposing slits and an annular shoulder lining the inner surface of the inner lip between the diametrically opposing slits. When attaching the cap to the aerosol container, the slits enable the resilient material of the inner lip to expand around a closure member that was fixedly secured to the neck of the container previously. Once the cap has been pushed onto the container to a certain extent, the inner lip contracts back into its original unexpanded position and the shoulder on the lip springs into a locking position beneath the bottom surface of the closure member. Unfortunately, such a cap assembly requires that the cap itself be manipulated and pressed onto the aerosol container. This is cumbersome and it increases the risk of unintentionally actuating the container since the top of the cap engages the stem of the aerosol container.
An example of a bushing that guides motion is found in U.S. Pat. No. 4,477,001 (Galia). The disclosed pressurized valve system uses a bushing to open and close a valve. A user presses on a platform to a linear extent and the valve opens to a greater linear extent with the aid of the bushing. The bushing has arms of looped material that connect to a central rod. The linear movement for pressing the platform is translated into a rotational movement by radially expanding the looped arms, which in turn translates the rotational movement back into a linear movement for the central rod. However, such a bushing is not configured to restrict axial motion or to lock in place.
Therefore, there has been a long-felt need for a bushing to expand into a locking position and permanently prohibit motion.